*Blue screenshot shows the Windows 8 operating system if you move the mouse pointer into the bottom-left corner of the Windows 8 Desktop. Click here for a screenshot of Windows 8 Start screen. Yellow screenshot shows Windows 8.1 which added an icon to the bottom left corner of the Desktop.

What if none of the icons match what I see?

You may have an uncommon operating system or an operating system such as Linux. Or you may have an operating system with a customized desktop. First read through the instructions for Windows and then Mac and attempt to identify the steps which work with your computer.